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Optically addressable defects in wide‐bandgap semiconductors are of considerable interest as materials platforms for quantum sensing and information systems. Density functional theory is used to identify novel defects in diamond consisting of transition metal + nitrogen complexes with potential for quantum sensing. Defects are characterized with respect to formation energy, ordering and degeneracy of the defect energy levels, optical and charge transition energies, zero‐field‐splitting energies, and thermodynamic stability. Novel defect sites with optically addressable spin states and viable spin sublevel configurations are identified, and analysis of activation energies for atomic migration indicates stability in the lattice. [ABSTRACT FROM AUTHOR]

Recent experimental observation of the first bilayer clusters B48−/0 reveals a new structural domain in boron nanostructures. Inspired by the previously reported bilayer B48, B54, B60, and B62 and based on extensive global‐minimum searches and density‐functional theory calculations, we predict herein a new series of medium‐sized bilayer boron nanoclusters C2 B64 (I), D2 B66 (II), D2 B68 (III), C1 B70 (IV), and Ci B72 (V) which all contain an elongated B46 bilayer hexagonal prism at the center with four effective interlayer 2c–2e B−B σ bonds formed between the top and bottom layers and the bilayer to core‐shell structural transition at B74 where core‐shell species start to dominate in thermodynamics, defining the up‐limit of the bilayer boron nanoclusters at B72. The newly obtained bilayer C2 B64 (I), D2 B68 (III), and C1 B70 (IV) appear to be systematically more stable than the previously reported cage‐like D4d B64, core‐shell C1 B68, and quasi‐planar C3v B70, respectively. Detailed bonding analyses indicate that these bilayer species follow the universal bonding pattern of σ+π double delocalization, rendering three‐dimensional aromaticity to the systems. The IR, Raman, and UV‐vis spectra of the concerned bilayer species are computationally simulated to facilitate their future characterizations. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of ternary AlxTiyNiz clusters, where x, y, and z are integers and x + y + z = 6, are investigated. Both Slater, Vosko, Wilks, and Nusair and B3LYP exchange‐correlation (XC) functionals are employed in a two‐stage density functional theory (DFT) calculations to generate these clusters. In the first stage, a minimum energy cluster structure is generated by an unbiased global search algorithm coupled with a DFT code using a light XC functional and small basis sets. In the second stage, the obtained cluster structure is further optimized by another round of global minimization search coupled with a DFT calculator using a heavier XC functional and more costly basis set. Electronic properties of the structures are illustrated in the form of a ternary diagram. Our DFT calculations find that the thermodynamic stability of the clusters increases with the increment in the number of constituent nickel atoms. These results provide a new insight to the structure, stability, chemical order, and electronic properties for the ternary alloy nanoclusters. [ABSTRACT FROM AUTHOR]

Structural and electronic properties of ternary clusters AlkTilNim, where k, l, and m are integers and k + l + m = 4, are investigated. These clusters are generated and studied by performing a two‐stage density functional theory (DFT) calculations using the Slater, Vosko, Wilks, and Nusair (SVWN) and Becke three‐parameter, Lee‐Yang‐Parr (B3LYP) functional exchange correlations. In the first stage, an unbiased global search algorithm coupled with a DFT code with a light exchange‐correlation and smaller basis sets are used to generate the lowest energy cluster structures. It is then followed by further optimization using another round of DFT calculation with heavy exchanged correlations and large basis set. Electronic properties of the structures obtained via the two‐stage procedure are then studied via DFT calculations. The results are illustrated in the form of ternary diagram. Our DFT calculations find that the stability of the cluster increases with the increase in the number of nickel atoms inside the clusters. Our findings provide new insight into the ternary metallic cluster through the structure, stability, chemical order, and electronic properties studies. Trimetallic nanoclusters are commonly studied for their interesting electronic and magnetic properties. However, there studies on this type of clusters with more than four atoms, conducted using unbiased initial configuration search, are rare and therefore timely. Here, one‐third of the uncovered AlkTilNim cluster structures are 2D planar, whereas the rest of the structures, but the highly nonsymmetrical Ti1Ni3, have trigonal pyramid‐like configuration. [ABSTRACT FROM AUTHOR]